What began with a son asking his father to help raise money for a paralyzed student-athlete turned into one of the Boston Marathon's most treasured traditions.

The wondrous sight of Dick Hoyt guiding son Rick's chair from Hopkinton to the Public Library has captivated crowds that have only grown since 1981, their maiden voyage into the marathon.

But as much as Dick Hoyt, a retired Air National Guard lieutenant colonel, has taken great care in preserving his physical fitness, especially over the past decade, he has decided this will be his last Boston, his 32rd with his son.

"My body is starting to tell me that it's time to slow down and cut back," said Hoyt, who turns 74 in June. "All my nerves are all knotted up in L4, L5 and L3 (vertebrae), and I have severe pain."

While this is the final marathon for Dick, this is not a farewell for Rick, who is now 52 and lives in his own apartment in Sturbridge. As a result of oxygen deprivation to his brain at birth, Rick was diagnosed as a spastic quadriplegic with cerebral palsy, preventing him from speaking.

Still, the Hoyts noted Rick's unique intellectual capacity and encouraged his educational drive. The Boston University graduate has been able to communicate via interactive computer since he was 10.

"Yes, I'm still planning on doing the Boston Marathon," Rick said via computer. "Dad and I have discussed and thought about it. We have decided to have someone from Team Hoyt that will be pushing me.

"I'd like to be out there on the course and still show people that yes, you can still be out there."

Rick Hoyt's future Boston Marathon partner likely will be Bryan Lyons, a dentist who practices in Billerica and lives in Methuen. "He's a great guy," Dick says. "Every once in a while, he visits Rick at his apartment, watches some movies with him and some popcorn.

"Rick and I never thought we'd be running marathons when he asked me to run in that first race," recalled Dick, whose Team Hoyt now competes out of Virginia Beach and San Diego, as well as New England.

When Rick was 15 and attending South Middle School in Westfield, he was at a Westfield State men's basketball game when he heard an announcement about a 5-mile road race to raise money for a lacrosse player who had been paralyzed from the waist down following an auto accident.

"Rick came home from that game and said, 'Dad, I have to do something for him. I want to let him know life goes on even though he's paralyzed. I want to run in the race.' "

Dick agreed to push Rick, albeit in an old Mulholland wheelchair. They finished the 5 miles, second to last, but it was indeed the beginning of a journey that has included more than 1,100 races, all over the world, from 5Ks to Ironman triathlons.

"After that first race, he said, 'Dad, when I'm running, it feels like my disability disappears,' which was a very powerful message to me," said Dick, who missed only the 2003 and '07 Boston with Rick since '81. "He called himself Freebird because now he was free to be out there running with everybody else."

To Dick, their first Boston holds special memories. "We had never run a marathon; the farthest we had ever run was 18 miles, and the very first Boston Marathon we ran was in 3 hours and 18 minutes, and we beat 85 percent of all the other runners."

"My favorite memory was in 1993, when I graduated from Boston University," Rick said. "Along the race, a lot of the people held up signs saying congratulations — 'Way to go, Rick.' "

Their best time was 2:40:39 in 1992, then just a little more than a half hour off the male runner's world record. While things have slowed in recent years, the duo had been going well on that fateful day last April 15.

"We were actually an hour ahead of our time the year before," Dick recalled. "Then at the 23-mile marker, I was noticing there was more police activity than usual. So I stopped and asked a police officer if there is something going on. He said two bombs have exploded at the finish line.

"We weren't stopped there, but to me, the marathon was over because my concern was all for our families, who were in the bleachers at the finish (across the street from the blasts). We kept running and just after the 25-mile mark (just before Kenmore Square), they stopped us at the bottom of the hill."

Ten members of Team Hoyt were still with Dick and Rick. "Five said they could walk to the Sheraton Boston (where Team Hoyt was to meet after the finish), and they said they could take Rick's chair."

Then someone from the crowd offered to drive the Hoyts to the Sheraton in his Jeep. The detour-filled mile took an hour and a half, with Rick on Dick's lap. Rick's everyday chair was at the VIP tent at the finish, which by then was a crime scene, so the chair wouldn't be retrieved until a couple of days later.

The Hoyts finally headed home, where a spare chair awaited, about 9 that night, after team members were all accounted for.

"I always pick on Rick, 'You're 52 years old, and you sat on my lap for five or six hours,' " Dick said.

"I just don't believe people could do something like that," he added of the bombings. "It bothered Rick for a long time."

In January, prospects weren't good for the Hoyts participating in this Boston. Dick hadn't run a stride since Thanksgiving, and even hobbled around the house with crutches at one point. He replaced his road work with three-hour cross-training sessions at the Conference Center in Southbridge, with swimming and no-impact reps on the cycle and elliptical, combined with upper-body exercises.

Hoyt also kept stretching several times daily and used the hot tub at his home on Hamilton Reservior a couple of times a day. He made progress enough to finish half marathons at Hampton Beach (Feb. 23) and New Bedford (March 16), still his only runs since Thanksgiving.

"The goal for this one is just to be able to finish," said Hoyt, who on April 10 underwent a cortisone injection to his lower back.

While he will miss the marathon rides with his dad, Rick remains eternally grateful.

"(His decision) was not surprising at all," he said. "My dad is getting older. My dad has meant a lot to me because he was always willing to push me and never say no."

CDL A DELIVERY DRIVERS Home Every Night! Needed for our Worcester Depot! Drive local - No more spending valuable nights away from your family! As a Direct Store Delivery Representative YOU have the opportunity to make a difference with our customers! Provide excellent customer service; interact in a positive manner with our customers; deliver our products to local stores. Be home every night! Work for a Company that has been around for over 80 years! Minimum of 3 months driving experience with CDL A/B; GED or HS diploma required; Must be able to drive a standard transmission. EEO/Veteran/Disability Growing Strong Since1933!